Programmable shape transformation of elastic spherical domes
Programmable shape transformation of elastic spherical domes
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DOI：
10.1039/c6sm00532b
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发表时间：
2016-01-01
期刊：
影响因子：
3.4
通讯作者：
Hsia, K. Jimmy
中科院分区：
文献类型：
--
作者：
Abdullah, Arif M.;Braun, Paul V.;Hsia, K. Jimmy
我们研究了失配应变驱动的球面穹顶的可编程形状变换，并报道了不同的几何和结构特征对外加失配应变对穹顶性能的影响。我们设想了一种双层穹顶设计，其中内层相对于被动外层的差异膨胀响应于穹顶环境的变化(例如引入有机溶剂)在双层系统内引入失配应变并导致穹顶形状变化。有限元分析表明，除了突穿式外，球面穹顶还经历了分叉屈曲和逐渐弯曲，随着失配应变的增加而变形为圆柱体。除了展示穿透能垒如何依赖于球形穹顶形状外，我们的分析还根据它们的失配应变变换构型关系识别了三组不同的穹顶几何形状。我们以聚合物为基础的弹性双层穹顶在有机溶剂中表现出不同的溶胀，实验定性地证实了有限元预测。我们证明，除了外部施加的刺激(失配应变)外，双层球面穹顶变形可以通过其几何和结构特征进行调整并因此进行编程。在刺激响应型功能设备的框架内加入弹性不稳定机制，例如快速穿透，可以改善它们的响应时间，否则它们的响应时间是由扩散控制的。因此，我们提出的设计指南可以用来实现可展开、多功能、可重新配置的结构，从而实现对多个长度尺度上的不同刺激集的响应。
We investigate mismatch strain driven programmable shape transformation of spherical domes and report the effects of different geometric and structural characteristics on dome behavior in response to applied mismatch strain. We envision a bilayer dome design where the differential swelling of the inner layer with respect to the passive outer layer in response to changes in dome surroundings (such as the introduction of an organic solvent) introduces mismatch strain within the bilayer system and causes dome shape transformation. Finite element analysis reveals that, in addition to snap-through, spherical domes undergo bifurcation buckling and eventually gradual bending to morph into cylinders with increasing mismatch strain. Besides demonstrating how the snap-through energy barrier depends on the spherical dome shape, our analysis identifies three distinct groups of dome geometries based on their mismatch strain-transformed configuration relationships. Our experiments with polymer-based elastic bilayer domes that exhibit differential swelling in organic solvents qualitatively confirm the finite element predictions. We establish that, in addition to externally applied stimuli (mismatch strain), bilayer spherical dome morphing can be tuned and hence programmed through its geometry and structural characteristics. Incorporation of an elastic instability mechanism such as snap-through within the framework of stimuli-responsive functional devices can improve their response time which is otherwise controlled by diffusion. Hence, our proposed design guidelines can be used to realize deployable, multi-functional, reconfigurable, and therefore, adaptive structures responsive to a diverse set of stimuli across multiple length scales.